Piston compressor derived from a reciprocating thermal engine

ABSTRACT

A compressor of the piston-type enclosed in a sealed housing. The specific cylinder head of the compressor is completed by an assembly of mass-produced internal combustion engine parts and the compressor is driven through the wall of the housing from an external motor.

The present invention relates to a compressor construction obtained byconverting a reciprocating thermal engine, notably for a refrigeratingfluid compressor of the open, semi-sealed or sealed type. Suchconversion is well known in the art and may be made in several ways suchas those presented, for instance, in U.S. Pat. Nos. 1,800,631 and1,804,873.

This invention is applicable to most reciprocating engines, whether ofthe oil or petrol cycle type, water-cooled or air-cooled, with orwithout liners, provided that they originally include a detachablecylinder head.

It is known that as far as low-power, single- or multi-cylindered pistoncompressors are concerned, whatever may be the type thereof (open,semi-sealed or sealed), production rates are extremely high, for theseapparatus correspond to wide-spread applications in household appliancessuch as refrigerators, small-scale air-conditioning, automobileair-conditioning, etc. In contrast thereto, when considering the powerratings corresponding to so-called industrial refrigation orcentral-station air-conditioning, for example, the production ratesseldom exceed a few thousands, or a few tens, of units per year,compared with several million units for low-power units. Since on theother hand the demand is divided among a relatively large number ofmanufacturers, it is obvious that notably for the construction of mediumor high-power piston compressors, most frequently of the open type, theproduction series are relatively small if not very small. This accountsto a large extent for the high cost of this equipment, and this highprice is also justified by the high-grade metal parts (free of anyporosity or cracks, perfectly homogeneous) required for the crankcasesand closing members in order to provide the necessary fluid-tightnessand bursting resistance.

Now, there is an obvious and pronounced "morphological" analogy betweenreciprocating thermal engines and compressors, and another obvious factis the considerable difference, in favour of thermal engines, betweenthe production costs of these two types of machines, this differencebeing due essentially to the consequence of mass production. The aim ofthe present invention is to carry out the conversion of a reciprocatingthermal engine into a compressor, notably a refrigeration one, in orderto take advantage of the low-cost of reciprocating thermal engines as aconsequence of the mass production of the main component elementsthereof, while adhering strictly to the specific requirements ofcompressors. This invention consists essentially, while maintainingamong the component elements of a reciprocating thermal engine those(notably the most expensive ones: cylinder-crankcase, movable device,oil pump) usable directly in the compressor version, in enclosing thecrankcase-cylinder unit in a fluid-tight welded steel andpressure-withstanding container, and providing the necessary functionalconnections between the crankcase-cylinder unit and the container(compressor drive, operating-fluid suction and delivery fittings, etc).

Thus, this invention is directed in general to a piston-type compressorstructure enclosed in a fluid-tight housing, characterized in that itsspecific compressor cylinder-head is completed by a set of mass-producedinternal-combustion engine parts, the compressor being driven throughthe fluid-tight housing from an external motor.

The compressor is generally secured to the cover of the fluid-tighthousing by means of its cylinder-head, either through a connectingmember secured to one end of the cylinder-head and by a connectingmember provided at the same end of the cylinder block and bearing on thesupport of the compressor driving members through the fluid-tighthousing, or the cover itself consists of the cylinder-head provided withadequate flanges and covers, the other component elements thereof beingfastened to said cylinder-head within the fluid-tight housing where theyare coupled to the compressor drive means extending through the housing.

Complementary fastening means secured to the various supports normallyprovided on the engine for mounting accessories unnecessary for thecompressor connect the latter to fastening points of the housing,notably in the case of the most important patterns.

The suction fitting will be carried directly by the housing, thecompressor sucking directly from the latter or through an external inletconnected directly to the cylinder-head while constituting at the sametime a securing member to the housing.

The drive is carried out through a flexible coupling housed within thehousing, the coupling being driven by a relatively short intermediateshaft journalled in bearings and provided with sealing means.

The flexible coupling, preferably of the type having a pair of coaxialpinions interconnected by a chain, will be connected to the intermediateshaft by means of a sliding-spline joint, notably in patterns suspendedfrom the cover-forming cylinder-head, thus facilitating the assemblingoperation.

Examples of embodiment of the invention will now be described withreference to the accompanying drawings.

In the drawings:

FIG. 1 shows a preferred embodiment of the invention;

FIGS. 2 and 3 illustrate variants of the embodiment shown in FIG. 1;

FIGS. 4 and 5 show an alternative embodiment of the invention.

In the exemplary of embodiment illustrated in FIG. 1, thecrankcase-cylinder unit (2) has been removed from the accessoriesrequired for its operation as a reciprocating thermal engine (such asfuel system, timing gear, ignition system, cooling system, flywheel,etc) and is provided with a suitable cylinder-head (3) of the automaticvalve type, for example for a liquid refrigerant. Thecarter/cylinder-head assembly is introduced into a housing (1) made ofthick steel plate assembled by welding, the cover (4) of which insuresthe holding of the carter/cylinder-head assembly in position ashereinafter described: a block (10) welded to the cover (4) is fastenedby means of studs (11) to the front end of the cylinder-head (3). On theother hand, the block (10) allows the passage of the delivery pipe (6).A bearing block (15) having its axis accurately aligned with the axis ofthe crankshaft (13) is welded to the cover (4). A connecting member (12)bolted to the cylinder block (2) bears on a journal portion of bearingblock (15) and absorbs the reaction torque during the compressoroperation. The cover (4) is itself rigidly fastened to the compressorhousing (1) by means of bolts (24) through registering flanges (19)welded to (1) and (4). The compressor is driven by means of a flexiblecoupling (14) secured to the securing flange or boss of crankshaft (13)in lieu and place of the conventional flywheel. The coupling (14) drivesan intermediate shaft (20) provided with a shaft packing (16) held inposition by the cover (17). The coupling (14) may advantageously consistof a pair of coaxial pinions interconnected by a Brampton chain.

If the basic engine is of a type such that the overhang of theabove-described arrangement is excessive (for instance in the case of asix-cylindered in-line engine), support arms (18) may be mounted on thelateral engine-supporting brackets (7). The arms, consisting ofcylindrical rods having a tapered end, engage circular bores withbevelled inlets formed in blocks (8) welded to the bottom (26) ofhousing (1), thus eliminating the overhang. If necessary, a skid orroller (9) may be provided for facilitating the introduction and properpositioning of the crankshaft and cylinder-block assembly into thehousing (1).

When assuming that brackets (7) were not provided or are in an awkwardposition, the side arms (18) may be secured as shown at (22) to the rearend of the cylinder-head (3) (FIG. 2), or in another position (23) onthe cylinder-block (in lieu and place of the water pump, or of thetiming gear case, or of any other engine accessory mounted on thisportion of the engine), as shown in FIG. 3.

If the operating fluid can be sucked without any inconvenience into thehousing (1), the inlet pipe (5) may be welded to any suitable locationto the housing (1), for example to the bottom (26) (FIGS. 1 and 2). Ifnot, the pipe (5) is then necessarily welded to the bottom (26) so thatits inner end projects into a suitable aperture in the cylinder-head(3), the tightness being obtained by means of a seal (25) (FIG. 3).

For compressor applications requiring a ready access to the automaticvalves, the modified embodiment illustrated in FIGS. 4 and 5 will bepreferred. In this variant, the cylindrical housing (30) comprises atits upper portion a rectangular aperture to which a frame made ofrelatively thick sections (36) is welded. The dimensions of this frame(36) are such that the cylinder-block (2), after the coupling (14)thereof has been previously fastened to the flywheel flange ofcrankshaft (13), can be lowered through this frame into the housing(30). The cylinder-head (31), rigidly fastened by means of bolts (35) tothe cylinder-block (2), bears with its lower surface through its flange(39) on the frame (36) and is secured thereto by means of bolts (37).The cylinder-head (31) is closed by a top cover (33) fastened by bolts(34) which allows direct access to the valve means. The structure of thecoupling (14) is similar to that described with reference to the variantshown in FIG. 1, except that:

the connecting bracket (12) can be dispensed with,

the intermediate shaft (20) drives the shaft (14) through slidingsplines, so that the shaft (20) can be moved to its operative positionby sliding when the cylinder-block (2) is positioned in the housing(30), after previously fastening the coupling (14) to the crankshaftflange (13). In this embodiment, the inlet pipe (32) and delivery pipe(38) are most conveniently disposed on the side faces of thecylinder-head, as in the example shown in FIG. 5.

I claim:
 1. A piston compressor of the sealed housing type, comprising aspecific compressor cylinder-head completed by an assembly of parts fora mass-production internal combustion engine including a cylinder-blockand driven through the sealed housing by an external motor by drivemeans passing through a support member, said compressor being adapted tofit with a cover of said sealed housing through its cylinder-head,wherein the compressor is secured to said cover by means of a firstcoupling member fixed on said cylinder-head and by a second couplingmember fixed on said cylinder-block and bearing on said support of saiddrive means of the compressor through said cover of said sealed housing.2. The compressor of claim 1, wherein said cover consists of acylinder-head provided with suitable flanges and covers, the othermembers of the compressor being fastened to said cylinder-head withinsaid sealed housing and coupled to drive means passing through saidsealed housing.
 3. The compressor of claim 1, wherein additionalfastening means, which are secured to bosses provided on thecylinder-block for mounting internal combustion engine accessories notused for the compressor, are provided for interconnecting the latter tofastening points on the sealed housing.
 4. The compressor of claim 1,wherein suction takes place through an external pipe connected directlyto the cylinder-head and adapted to constitute a securing member to thesealed housing.
 5. The compressor of claim 1, wherein the drive meanscomprise a flexible coupling disposed within the housing, the couplingbeing driven through a short intermediate shaft journalled in bearingsand provided with sealing means.